The present invention provides a method for fabricating a pixel cell of CMOS image sensor, comprising: preparing a semiconductor substrate divided into region I and region II; forming an insulation layer on the surface of the semiconductor substrate in the region I and a gate dielectric layer on the surface of the semiconductor substrate in the region II; forming a poly-silicon gate on the surface of the semiconductor substrate in the region II; forming a deep doped well in the region I through an ion implantation with high energy; performing an ion implantation with low energy in the region I and an ion implantation for lightly doped source/drain in the region II simultaneously; and forming source/drain regions in the semiconductor substrate in the region II.